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Redis XTRIM in Golang (Detailed Guide w/ Code Examples)

Use Case(s)

The XTRIM command in Redis is used to trim the length of a stream to a given maximum number of items. In Golang, this command is useful when you want to limit the memory footprint of your Redis streams, particularly in scenarios where you have a high volume of data flowing in but only need to maintain a certain window of recent activity.

Code Examples

Here's an example of how to use the XTRIM command in Golang using the go-redis/redis/v8 client:

package main import ( "context" "fmt" "" ) func main() { ctx := context.Background() rdb := redis.NewClient(&redis.Options{ Addr: "localhost:6379", Password: "", // no password set DB: 0, // use default DB }) // Trimming a stream to have at most 1000 entries xTrimMaxLen := int64(1000) trimmedCount, err := rdb.XTrimMaxLen(ctx, "mystream", xTrimMaxLen).Result() if err != nil { panic(err) } fmt.Printf("Trimmed %d entries from the stream\n", trimmedCount) }

In this example, we create a new Redis client connected to the local instance. We then use the XTrimMaxLen method to trim the stream named "mystream" to a maximum length of 1000 entries. The result tells us how many entries were removed from the stream as part of the trimming process.

Best Practices

  • Ensure that you handle the error properly after executing the XTRIM command.
  • It's good practice to wrap your Redis commands inside a context with timeout, especially in production environments, to avoid long-running commands that could block other operations.
  • When specifying the maximum length for the XTRIM command, be sure it aligns with your application's data retention policy and use case.

Common Mistakes

  • Not handling errors that may occur when running the XTRIM command.
  • Using XTRIM without understanding its impact on data retention—once data is trimmed, it cannot be recovered.


Q: Is it possible to automatically trim a stream to a certain size on each insert?

A: Yes, you can use the XADD command with the MAXLEN option to automatically trim the stream every time a new entry is added. This is often more efficient than calling XTRIM separately.

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Dragonfly is fully compatible with the Redis ecosystem and requires no code changes to implement.